If you have reached this page then I am sure you have recently upgraded your WordPress to 3.4 and have received below error and if you are going to upgrade your wordpress to 3.4 then deactivate db related plugins and upgrade.
Fatal error: Call to undefined method dbrc_wpdb::delete() in /your-path-to-wordpress/wp-includes/option.php on line 370
This error comes because you may have few incompatible plugins to WordPress 3.4 which uses database for their functionality.
1) Take backup of files/database before you proceed.
2) Go to wp-contents folder.
3) Take backup of db.php file to your system.
4) Delete db.php
5) Check WordPress admin dashboard again. It should show error message and ask you for “Upgrade Complete”. Just click it. If it works then skip below steps and if admin dashboard is still not working then follow below steps.
6) Go to /wp-content/plugins/ folder.
7) You may have either db-cache or db-cache-reloaded-fix folder in /wp-content/plugins/
8) Take backup of db-cache/db-cache-reloaded-fix folder to your system.
9) Delete that folder from your server. (If anything goes wrong, you can upload backup back to your server 🙂 )
10) Check WordPress Admin Dashboard now. It should show error message and ask you for “Upgrade Complete”. Just click it. If it works then congrats yourself 🙂 .
11) If everything works fine then you can upload latest version of DB Cache Reloaded Fix from your “Add New Plugin” page.
12) If everything works fine for you but not “Add New Post” page then just reinstall wordpress from Dashboard -> Updates -> Click “Re Install Now” button.
Not yet Upgraded to WordPress 3.4 :
If you haven’t upgraded your wordpress to 3.4 yet then you are lucky one. If you are thinking to upgrade now then please deactivate your db related plugins like Db Cache or DB Cache fork and then proceed to upgrade.
(Remember, all above steps have worked for me for all my 10 setup of wordpress which have different combination of plugins but it may not work for you if you have custom plugin or less popular plugins.)
Note : Please take backup of all your resources (files/database) before following this steps. I am not taking any responsibility for your loss because of following above steps. If you are not sure with this, please take wordpress expert’s help.